Many types of input devices are presently available for performing operations in a computing system, such as buttons or keys, mice, trackballs, touch panels, joysticks, touch screens and the like. Touch screens, in particular, are becoming increasingly popular because of their ease and versatility of operation as well as their declining price. Touch screens may include a touch panel, which may be a clear panel with a touch-sensitive surface. The touch panel may be positioned in front of a display screen so that the touch-sensitive surface covers the viewable area of the display screen. Touch screens may allow a user to make selections and move a cursor by simply touching the display screen via a finger or stylus. In general, the touch screen may recognize the touch and position of the touch on the display screen, and the computing system may interpret the touch and thereafter perform an action based on the touch event.
One limitation of many conventional touch panel technologies is that they are only capable of reporting a single point or touch event, even when multiple objects come into contact with the sensing surface. That is, they lack the ability to track multiple points of contact at the same time. Thus, even when two points are touched, these conventional devices only identify a single location, which is typically the average between the two contacts (e.g. a conventional touchpad on a notebook computer provides such functionality). This single-point identification is a function of the way these devices provide a value representative of the touch point, which is generally by providing an average resistance or capacitance value.
Moreover, detecting and processing of events detected on a sensor panel can take a significant amount of processing power. The significant amount of processing can make a processor too busy to perform other functions and can slow down devices using a sensor panel. Additionally, processors typically consume a significant amount of power during operation, which can be particularly problematic when a sensor panel is used in conjunction with a hand held device, as many hand-held devices have a limited power supply.